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#![warn(rust_2018_idioms)]
#![cfg(feature = "full")]
use std::pin::Pin;
use std::task::{Context, Poll};
use tokio::io::{AsyncRead, AsyncReadExt, ReadBuf};
use tokio_test::assert_ok;
use tokio_test::io::Builder;
#[tokio::test]
async fn read_to_end() {
let mut buf = vec![];
let mut rd: &[u8] = b"hello world";
let n = assert_ok!(rd.read_to_end(&mut buf).await);
assert_eq!(n, 11);
assert_eq!(buf[..], b"hello world"[..]);
}
#[derive(Copy, Clone, Debug)]
enum State {
Initializing,
JustFilling,
Done,
}
struct UninitTest {
num_init: usize,
state: State,
}
impl AsyncRead for UninitTest {
fn poll_read(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
buf: &mut ReadBuf<'_>,
) -> Poll<std::io::Result<()>> {
let me = Pin::into_inner(self);
let real_num_init = buf.initialized().len() - buf.filled().len();
assert_eq!(real_num_init, me.num_init, "{:?}", me.state);
match me.state {
State::Initializing => {
buf.initialize_unfilled_to(me.num_init + 2);
buf.advance(1);
me.num_init += 1;
if me.num_init == 24 {
me.state = State::JustFilling;
}
}
State::JustFilling => {
buf.advance(1);
me.num_init -= 1;
if me.num_init == 15 {
// The buffer is resized on next call.
me.num_init = 0;
me.state = State::Done;
}
}
State::Done => { /* .. do nothing .. */ }
}
Poll::Ready(Ok(()))
}
}
#[tokio::test]
async fn read_to_end_uninit() {
let mut buf = Vec::with_capacity(64);
let mut test = UninitTest {
num_init: 0,
state: State::Initializing,
};
test.read_to_end(&mut buf).await.unwrap();
assert_eq!(buf.len(), 33);
}
#[tokio::test]
async fn read_to_end_doesnt_grow_with_capacity() {
let arr: Vec<u8> = (0..100).collect();
// We only test from 32 since we allocate at least 32 bytes each time
for len in 32..100 {
let bytes = &arr[..len];
for split in 0..len {
for cap in 0..101 {
let mut mock = if split == 0 {
Builder::new().read(bytes).build()
} else {
Builder::new()
.read(&bytes[..split])
.read(&bytes[split..])
.build()
};
let mut buf = Vec::with_capacity(cap);
AsyncReadExt::read_to_end(&mut mock, &mut buf)
.await
.unwrap();
// It has the right data.
assert_eq!(buf.as_slice(), bytes);
// Unless cap was smaller than length, then we did not reallocate.
if cap >= len {
assert_eq!(buf.capacity(), cap);
}
}
}
}
}
#[tokio::test]
async fn read_to_end_grows_capacity_if_unfit() {
let bytes = b"the_vector_startingcap_will_be_smaller";
let mut mock = Builder::new().read(bytes).build();
let initial_capacity = bytes.len() - 4;
let mut buf = Vec::with_capacity(initial_capacity);
AsyncReadExt::read_to_end(&mut mock, &mut buf)
.await
.unwrap();
// *4 since it doubles when it doesn't fit and again when reaching EOF
assert_eq!(buf.capacity(), initial_capacity * 4);
}